1. Field of the Invention
The present invention relates to a recording medium playback device and a recording medium playback method.
2. Description of the Related Art
Data is recorded in an optical disk recording medium, such as a compact disc, a DVD, a Blu-ray disc, or the like, for example, by forming pits on the surface of the recording medium. Information in the form of digital data is recorded by repeatedly collocating the pits (also called the “marks”) with lands (also called the “spaces”) outside the pits. The data that is recorded in the recording medium is generally played back using an optical disk drive apparatus. The optical disk drive apparatus irradiates the marks and the spaces of the recording medium with a light beam and reads the data based on differences in reflection from the marks and the spaces.
The data that is read undergoes signal processing by an RF processing portion and a frame synchronization signal (FS) detection and synchronization protection portion that are provided in the optical disk drive apparatus, as shown in FIG. 11, and is played back. FIG. 11 is a block diagram that shows the RF processing portion and the FS detection and synchronization protection portion of a known optical disk drive apparatus. When the data recorded in the recording medium is played back, a pickup and RF amp portion 6 first reads the digital data based on the marks and spaces on the recording medium. The RF processing portion 10 then performs binarization processing of the digital data, and a playback signal is output by the FS detection and synchronization protection portion 30. The RF processing portion 10 includes, for example, a PLL 12, an A/D conversion portion 14 and a PR equalization and maximum likelihood decoding binarization portion 16.
Next, the FS detection and synchronization protection portion 30 detects a frame synchronization signal in a data string in the binarized playback signal. The FS detection and synchronization protection portion 30 includes, for example, an FS detection portion 32, a synchronization state control and timing counter portion 34, and an FS synchronization protection setting register portion 36. Next, a demodulation and ECC correction/address decoding portion 50 performs demodulation and address decoding of the playback signal data string, based on timing information that is detected by the FS detection and synchronization protection portion 30. The detection of the frame synchronization signal is ordinarily performed by pattern matching to a unique pattern that is defined by the format as a synchronization pattern.
Various processing methods are available to perform the binarization processing of the digital data signal that is recorded in the recording medium, but in recent years, partial response maximum likelihood decoding (PRML) processing has come to be used for optical disk playback.
Note that technologies related to the detection of the synchronization signal are disclosed in Japanese Patent Application Publication No. JP-A-2001-243727, Japanese Patent Publication No. 3697809, and Japanese Patent Publication No. 3377669.